HFT Nasal Cannula 临床研究(4)

An abstract-only study achieved 95.75% relative humidity with the F&P system versus 98.75% with Vapotherm at flow rates of 1–8 L/min, although the F&P system was not set up according to manufacturer recommendations.Both systems appear to effectively heat and humidify gases.

仅抽象研究结果表明在流速率为1–8 L/min时，F&P系统相对湿度为95.75%，Vapotherm相对湿度为98.75%，尽管F&P系统此时没有按照厂家推荐规范来操作。8这两种系统都能产生有效的增温增湿的气体。 DOES HHFNC DELIVER POSITIVE AIRWAY PRESSURE? HHFNC 能传递正气道压吗？

With regard to the question of whether or not HHFNC is a form of CPAP, we might first ask whether it delivers positive airway pressure, and if so, whether the pressure is, or might expected to be, consistent, predictable, and regulated. It should be noted that although Vapotherm and HHFNC are not synonymous in that there are other devices that may provide HHFNC, to the author’s knowledge all of the limited evidence available to date in the neonatal and pediatric scientific literature is confined to studies and reports of Vapotherm. Unless otherwise noted, all studies quoted are available only in abstract form, underscoring the lack of quality published evidence.

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关于HHFNC是不是CPAP的一种表现形式这个问题，我们首先要了解HHFNC 能否传递正气道压，如果可以，这种气压是否或可能成为一种持续的、可预测的、有规律的气压。值得注意的是，尽管Vapotherm 和 HHFNC并非等意的，可能有其他设备也能提供HHFNC疗法，作者从迄今为止新生儿和小儿科科学文献中得到局限于Vapotherm研究报告的有限论证。除非另行通知，否则所有研究引用都源自抽象形态，下划线表明没有有效的质量报告。

In a bench study using Vapotherm and a simulated lung with a variable leak to mimic in vivo leaks, CPAP of 0.5–4.5 cm H2O was generated at flow rates of up to 8 L/min, and the authors concluded that unless the mouth is closed and the leak around the nares minimized, it is unlikely that the Vapotherm nasal cannula delivers a clinically relevant level of CPAP.A further study measured oropharyngeal pressures in 6 healthy adults using Vapotherm, and showed a small but consistent absolute increase in oropharyngeal pressure during all phases of the respiratory cycle from 1.1 cm H2O at zero flow to 4.5cm H2O at 40 L/min, with the measured increase highly correlated with flow rate.These studies suggest that only modest pressures were generated with Vapotherm and that a relationship between flow and pressure exists as expected. A follow-up study from

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the same group involving 16 neonates of highly variable birth weight and gestation recorded oral cavity pressure on Vapotherm at flow rates between 1 and 5 L/min.With the mouth open, no pressure was generated at any flow rate. With the mouth closed, oral cavity pressure was related to flow rate and weight, with the highest recorded pressure of 4.8 cm H2O at a flow rate of 4 L/min in the 2 smallest neonates. The authors concluded that HHFNC should not be used as a replacement for delivering CPAP. Although this conclusion seems to be based on the lack of significant pressure generated in many cases, it is worth noting that the smallest and least mature neonate(s) in the study was (were) of 900 g and 29.1 weeks’ gestation (it is unclear if these were the same patient). This raises the strong likelihood that smaller neonates and higher flows would result in significantly higher generated pressures.

在利用Vapotherm作用于一个模拟体内不稳地泄漏的肺，CPAP在流速率达8 L/min时产生0.5–4.5 cm氧气，得出的结论是除非嘴闭上并最小化鼻孔周围的气体泄漏，否则Vapotherm鼻套管不大可能达到CPAP临床水平。9利用Vapotherm深入研究6位健康成人的呼吸道压力，结果表明在呼吸周期从流速率为0时的1.1 cm氧气到流速率为40 L/min 时的4.5cm氧气的各个阶段中，呼吸道压力始终保持小量上升。上升量与流速率有很大关系。这些研究表明Vapotherm会产生最合适的气

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压，气压和流速的关系也与实验预料一致。后续试验中， 16名初生重量不一致的新生儿和妊娠记录利用Vapotherm流速率在1 L/min和 5 L/min之间的口腔压。当嘴张开时，在任何流速率下都不会产生气压。当嘴闭上时，口腔压与流速率和体重有关。气压最高记录在2个最小的新生儿在流速率为4 L/min产生4.8 cm氧气。我们得到的结论是HHFNC不应当做一种传递CPAP的替代品。虽然此结论并非建立在有很多产生重要气压意义的案例上，但值得关注的是试验中最小的新生儿体重900克，29.1周妊娠期（不清楚是否指同一患者）。这一结果表明较小的新生儿和较大的流速很可能导致产生更高的压力。

Of further concern is a bench study of nasal cannula, CPAP, and Vapotherm examining the effect of flow on temperature, humidity, pressure, and resistance.Although gas delivered by Vapotherm was more humid than that via nasal cannula and CPAP, Vapotherm produced substantially higher pressure and resistance that may have clinical relevance such as increased WOB. It is unclear from this abstract-only study how and where the pressure and resistance were measured, highlighting the difficulty of appropriately assessing such evidence. 我们进一步关心的实验是鼻套管、CPAP和Vapotherm流速在温度、湿度、压力和抗阻力等方面的效果。虽然经Vapotherm产生的气体比经鼻插管和CPAP产生的气体更加湿润，但Vapotherm能产生可能有临床

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意义的实质上更高的气压和更强的耐受性，比如像增加了的呼吸功。此抽象实验不能清楚的说明测量气压和耐受性的位置、如何测量，从而突出此类似论证的恰当评估的难度。

Given the lack of any specific peer-reviewed publications examining HHFNC and generated pressures, it is useful to review and extrapolate data from 2 such studies using nonhumidified low-flow nasal cannula. The first examined esophageal pressure and thoracoabdominal motion in 13 preterm neonates at gas flow levels of 0.5–2 L/min delivered by nasal cannula, with an outer diameter of either 0.2 or 0.3 cm.The smaller nasal cannula did not deliver pressure or alter thoracoabdominal motion at any flow, whereas the 0.3-cm nasal cannula delivered positive end-distending pressur …… 此处隐藏：3592字，全部文档内容请下载后查看。喜欢就下载吧 ……